To carry out an analysis of the line profiles, it is crucial to have a spectrum with a high S/N. Indeed, this parameter is crucial to examine in detail the wings of profiles, and to obtain an accurate decomposition [1]}. Therefore, we combined together all the spectra obtained by the VLT, reaching a S/N\(\sim \) 90 in the continuum around 5100Å. Although we may lose some information on the variability in the continuum and permitted lines over the six months of observations, this operation is necessary to ensure a good quality spectrum that can be studied in detail. The combined spectrum is shown in Fig. REF . All of the fitting procedures that follow have been performed with our own Python code [2]}. An analysis of the variability will instead be carried out in Sect. . In our line profile analysis, we focused on the most prominent lines: H\(\beta \) , [O III]\(\lambda \lambda \) 4959,5007, the [S II]\(\lambda \lambda \) 6716, 6731 doublet, and the H\(\alpha \) +[N II]\(\lambda \lambda \) 6548,6584 complex.
